GL-1
Cisco 10000 Series Router Software Configuration Guide
OL-2226-23
G L O S S A R Y
A
AAA
authentication, authorization, and accounting (pronounced “triple a”).
AAL5
ATM adaptation layer. This layer maps higher layer user data into ATM cells, making the data suitable
for transport through the ATM network.
ABR
Available bit rate. QoS class defined by the ATM Forum for ATM networks. ABR is used for
connections that do not require timing relationships between source and destination. ABR provides no
guarantees in terms of cell loss or delay, providing only best-effort service. Traffic sources adjust their
transmission rate in response to information they receive describing the status of the network and its
capability to successfully deliver data.
ACL
Access Control List. A list kept by routers to control access to or from the router for a number of
services (for example, to prevent packets with a certain IP address from leaving a particular interface
on the router).
ADSL
Asymmetric digital subscriber line. A digital subscriber line (DSL) technology in which the
transmission of data from server to client is much faster than the transmission from the client to the
server.
ATM
Asynchronous Transfer Mode. International standard for cell relay in which multiple service types
(such as voice, video, or data) are conveyed in fixed-length cells. Fixed-length cells allow cell
processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of
high-speed transmission media such as E3, SONET, and T3.
authentication
A security feature that allows access to information to be granted on an individual basis.
B
bandwidth
The range of frequencies a transmission line or channel can carry. The greater the bandwidth, the
greater the information-carrying capacity of a channel. For a digital channel this is defined in bits. For
an analog channel it is dependent on the type and method of modulation used to encode the data.
BBA
Broadband Aggregation.
BGP
Border Gateway Protocol. Interdomain routing protocol that exchanges reachability information with
other BGP systems. It is defined in RFC 1163.
bps
Bits per second. A standard measurement of digital transmission speeds.
bridge
A device that connects two or more physical networks and forwards packets between them. Bridges can
usually be made to filter packets, that is, to forward only certain traffic.
